48 



FAEM BUILDINGS IN SOUTH AFRICA 



Brick Corbelling.— (See Fig. 42.) 



Corbelling is an artifice employed to form a ledge to carry a wall- 

 plate, the ends of joists, etc. The amount of projection of each course 

 of brickwork, beyond the one immediately below it, should be less, 

 the greater the weight to be borne. In the figure it is 1^ inches. It 

 should on no occasion exceed 2 inches. 



Off-sets.— (See Fig. 43.) 



An offset is a ledge formed in a wall by suddenly reducing its 

 thickness, as for instance in passing from a lower to an upper storey. 

 On the ledge a wall-plate may be supported. An offset is frequently 

 used to support the plates for ground floors. 



Copings. — A wall which is unprotected by a roof, as for instance 

 a yard wall, should be provided with a coping to prevent rain from 



1 II 



Fig. 42. 



Fig. 43. 



Fig. 44. 



Fig. 44a. 



percolating into the body of the wall. Sometimes the coping is made 

 to project beyond the face of the wall on each side, but this should 

 never be the case in yards where cattle are to be confined, on account 

 of the danger of the animals' horns breaking off lengths of the coping. 



A coping, finished in cement mortar, is shown in Fig. 44. Here 

 a line of stretchers, S, is laid along the middle of the top of the wall, 

 the corners being filled in with brick chips C, and the whole plastered 

 over with one to three cement mortar, and finished off smoothly to a 

 semi-circular section. 



Specially impermeable, purpose-made bricks are occasionally obtain- 

 able for copings. They should be laid in cement mortar. A form 

 suitable for farm purposes is illustrated by Fig. 44a, in cross-section, 



